221000981 has 2 divisors, whose sum is σ = 221000982. Its totient is φ = 221000980.

The previous prime is 221000971. The next prime is 221001031. The reversal of 221000981 is 189000122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 220997956 + 3025 = 14866^2 + 55^2 .

It is a cyclic number.

It is not a de Polignac number, because 221000981 - 2¹⁰ = 220999957 is a prime.

It is a super-2 number, since 2×221000981² = 97682867205924722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221000911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110500490 + 110500491.

It is an arithmetic number, because the mean of its divisors is an integer number (110500491).

Almost surely, 2^221000981 is an apocalyptic number.

It is an amenable number.

221000981 is a deficient number, since it is larger than the sum of its proper divisors (1).

221000981 is an equidigital number, since it uses as much as digits as its factorization.

221000981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 221000981 is about 14866.1017418824. The cubic root of 221000981 is about 604.5952541807.

The spelling of 221000981 in words is "two hundred twenty-one million, nine hundred eighty-one", and thus it is an aban number.